| http://www.w3.org/ns/prov#value | - In accomplishing these and other objects of the invention, I have provided improved structure, the preferred forms of which are illustrated in the accompanying drawings, wherein: FIG. 1 is a vertical section through the lower portion of a bore hole, and showing a drilling string therein having a drill bit on the lower end thereof, and provided with one or more reamers constructed in accordance wit
|
